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It's just that the French left the greastet Easter Egg of all time when creating the Metric System. They could've just made speed of light some round number, e.g. 1 million km/sec, but that sounded too bland, so they chose the Great Pyramid of Giza instead. The same for the charge of the electron
If you make that number round, others become not-round.

I read [0] that the meter was defined as 1 / 10,000,000th of the distance from the equator to the (north?) pole. The measurement on which that was based was wrong and the actual distance is 10,001,966 meters. If you make that distance round, then the speed of light will almost certainly not be round (now that would be a coincidence!).

But also 1 cm^3 = 1 ml. Perhaps the ml was based on the cm^3. That's practical.

Making a round number for the speed of light or for the distance from equator to pole is practical only for geographers or physicists. What would be most practical to ordinary people as the basis for a meter? A body part (is there a particularly standard body part, with minimal correlation with body size/mass)?

[0] I haven't seen an especially reliable source

The conspiracy theorist inside me would say that the French might not be the first to define the metric this way /s.
"Of course it's a coincidence" doesn't leave me with good feels. See, we don't know what a "normal distribution" is for a correlation like this, it's not like we have a huge bag of samples to determine the variance from.
Something has to lie on that line of latitude. Has anyone checked what is on the southern speed of light latitude?
The pyramid exists on every latitude between 29.9782000 and 29.9801000, it's not that precise.
Is it a coincidence that the diameter of Earth orbit is 1000 light seconds, or that our Moon perfectly eclipses Sun? The Pyramid is a comparatively modest example.